Abstract: Water-absorbent crosslinked polymers bearing acid groups, some or all of the acid groups being present as carboxylate groups having at least two different types of cations as counterions, processes for their preparation and mixtures of water-absorbent crosslinked polymers.

Abstract: A color-stable superabsorbent polymer having long-term color stability, and methods of manufacturing the polymer, are disclosed. The color-stable superabsorbent polymer is prepared in the essential absence of a persulfate, and is subjected to a low dose of ultraviolet radiation. The resulting superabsorbent polymer resists color degradation during periods of extended storage, even at an elevated temperature and humidity.

Abstract: A color-stable superabsorbent polymer having long-term color stability, and methods of manufacturing the polymer, are disclosed. The superabsorbent polymer is prepared using a sulfinic acid derivative, like 2-hydroxy-2-sulfinatoacetic acid, a salt thereof, or a mixture thereof, as the reducing agent in a polymerization initiator system for the preparation of a superabsorbent polymer from monomers. The resulting superabsorbent polymer resists color degradation during periods of extended storage, even at an elevated temperature and humidity.

Abstract: Water-absorbent crosslinked polymers bearing acid groups, some or all of the acid groups being present as carboxylate groups having at least two different types of cations as counterions, processes for their preparation and mixtures of water-absorbent crosslinked polymers.

Abstract: A color-stable superabsorbent polymer composition having long-term color stability, and methods of manufacturing the composition, are disclosed. The superabsorbent polymer composition contains an inorganic reducing agent and an optional metal salt, and resists color degradation during periods of extended storage, even at an elevated temperature and humidity.

Abstract: Surface-tested superabsorbent polymer particles obtained by mixing 100 parts by weight of superabsorbent polymer particles with 0.001 to 10 parts by weight of a hydroxyalkylamide, and heating the surface-treated superabsorbent polymer particles to crosslink molecular chains existing at least in the vicinity of the surfaces of the superabsorbent polymer particles is disclosed. Surface crosslinking the superabsorbent polymer particles with a hydroxyalkylamide substantially increases both the rate of liquid absorption and the quantity of liquid absorbed and retained by the superabsorbent particles.

Abstract: A new and improved method of manufacturing an acrylic acid superabsorbent polymer, that is manufactured by any known technique, except that the acrylic acid monomer is polymerized to substantial completion before neutralization, and neutralization is accomplished by admixing a solid, e.g., powdered or granular, neutralizing agent into the acrylic acid polymer. Preferably, the neutralizing agent is a solid, non-hydroxide neutralizing agent, such as sodium carbonate, potassium carbonate, ammonium carbonate or mixtures thereof. Cross-linking may be accomplished during polymerization, simultaneously with neutralization, or cross-linking may be carried out in a separate processing step subsequent to neutralization, or both.